Heating unit for incinerators



Feb. 1, 1955 J. w. HEBERT HEATING UNIT FOR INCINERATORS 2 Sheets-Sheet 1Filed Feb. 1, 1952 INVENTOR ATTOR'NEY Feb. 1, 1955 J. w. HEBERT2,701,294

HEATING UNI T FOR INCINERATORS Filed Feb. 1, 1952 2 Sheets-Sheet 2INVENTOR ATTORNEY United States Patent HEATING UNIT FOR INCINERATORSJohn W. Hebert, Bay City, Mich., assignor, by mesne assignments, toCalcinator Corporation, Bay City, Mich.

Application February 1, 1952, Serial No. 269,515

7 Claims. (Cl. 219-35) This invention relates to electric heating unitsand more particularly to heating units of the type used in dehydratingand igniting garbage in garbage disposal incinerators and the like.

One of the primary objects of my invention is to design a heating unitwhich can be mounted in the wall of the combustion chamber of adowndraft incinerator and thus serve to not only directly dehydrate andignite the refuse in the charging chamber, but also to pro-heat theincoming air flowing upwardly between the inner and outer walls of theincinerator and thence into the combustion chamber.

Another object of the invention is the provision of a heating device ofthe type described which includes battle means for protecting the outerwall of the incinerator from excessive heat radiation at the point ofmounting of the device.

A further object of the invention is to provide an electric heater unitwhich includes a stamped alloy sheath of substantial surface area with aheater element in facial contact therewith, thereby increasing theradiation surface of the unit and contact with the refuse to be burned,as well as the rate at which the heat can be taken from the heater unit.

A further object is to provide a sheath of substantial surface area forthe heating element so that the temperature of the heat-emitting surfacerises slowly and evenly to ignition temperature, thus providing adehydratmg period for drying and driving off odors gradually, therebyassuring combustion of all materials or refuse in the charging chamber.

A further object still is to provide a sheathed element which makespossible a drying period of varying length, said period being varied byintermittently supplying electric current to the device.

A further object still is to provide means for retaining the free endsof the substantially annular heating element in parallel, spacedrelation, thus eliminating the possibility of damaging short circuits.

Another object is to provide an electric heating device which can alsobe positioned to pre-heat the charging air flowing upwardly between theinner and outer walls of the incinerator, thereby increasing thecirculation rate of the air.

A still further object is to provide such a heating device which iseasily mountable and demountable in the incinerator, and which is easilyaccessible for inspection and/or repair should such inspection andrepair become necessary.

A still further object is to provide an electric heating unit composedof a minimum number of parts all of which can be easily and economicallymanufactured and assembled.

Other objects and advantages of the invention Wlll become apparentduring the course of the following descrip tion wherein:

Fig. 1 is a fragmentary, front elevational v1ew showing my heating unitmounted in the inner wall of the combustion chamber of an incinerator,the baffle plate being broken away to more clearly show the assembly.

Fig. 2 is a vertical, edge elevational view thereof.

Fig. 3 is a face view of the electric heating element only.

Fig. 4 is an edge elevational view thereof.

Fig. 5 is a side elevational view of an incinerator showing my electricheating unit in place therein, parts being broken away to more clearlyshow the mounting and location of the unit.

ice

Referring now more particularly to the accompanying drawings in which Ihave shown one embodiment of my invention, and wherein is shown anincinerator casing H comprising front, side and rear walls 6, 7 and 8respectively, and having a charging opening 9 in the top 10 thereof,with a hinged door D forming a closure for same.

The walls of the casing are properly insulated with sheet insulation 11,and an inner shell 12 is hung in the casing to form a combustion chamberC in which refuse and garbage (not shown) are placed, said shell beingspaced from the walls of the casing H to form air passages therebetween,and a grate G is reciprocatingly mounted on the tracks 14 provided insaid casing.

The grate G forms the bottom of the inner shell 12 and is of greaterarea than the lower open end thereof, said grate being formed with aforwardly projecting lug 15, and for a purpose to be presentlydescribed.

A transversely disposed shaker rod 16 spans the casing H, and isjournaled in bearings (not shown) provided in the side walls 7, one endof the rod projecting through one of said side walls to accommodate acrank (not shown) as usual.

A depending leg 17 is provided on the shaker rod 16 at a pointintermediate its length, the free end of said leg extending into anopening 18 provided in the lug 15 of the grate G, so that the grate maybe reciprocated as the shaker rod is actuated.

An opening 19 is provided in the front wall 6 of the casing H, and anash drawer 20 extends into said opening below the grate G so that ashdislodged from the grate as it is actuated is discharged into saiddrawer, the front end 21 of said drawer normally forming a closure forsaid opening. The refuse etc. is fed to the combustion chamber throughcharging door 11 and air flows upwardly between the outer casing shelland the combustion chamber, thence downwardly over and through therefuse, and thence out through a smoke pipe 22 provided in the rear wall8 to atmosphere.

The above describes an incinerator such as shown in Patent No.2,488,405, issued to me under date of November 15, 1949, and I do notdeem it necessary to show and describe it in further detail, as theinstant invention is directed broadly to the electric heating unit andcombination with the incinerator.

The heating unit proper comprises a sheath S formed of substantiallydisc-shaped plates 23 and 24 respectively, these plates being preferablyformed of stainless steel with the outer edges pressed inwardly as at25, and these edges are welded together with the heating element Einterposed between the plates, said element including a tube 26 formedof an alloy of proper characteristics for heat dissipation and corrosionresistance, and co-extensive therewith and embedded therein is aresistance wire 27, the free ends of which extend a predetermineddistance from the ends of the tube. Semi-circular, inwardly pressedareas 28 are provided in each plate as shown, and are disposed in facialcontact when assembled, and a plurality of vents or louvers 29 arestamped in said inwardly pressed areas for ventilation and release ofexcess heat which might otherwise destroy the element. These contactingareas 28 conduct the heat away from the electric element and at greaterrange than would occur if the heater element were spaced uniformly fromthe sheath at all points.

An opening 30 is provided in the lower edge of the sheath S and theplate 24 is cut away as at 31 to accommodate the outwardly bent sections32 of the heating element, which lead downwardly therefrom inspaced-apart relation, as clearly shown in Fig. 4 of the drawings,terminals 33 being provided on the ends of the wire 27 for connection oflead wires 34 which lead to a source of electrical energy.

An opening 35 of substantially the same shape as the sheath S isprovided in the wall 12 of the inner shell, and the edge 25 of theheating unit fits the marginal edge of said opening, and is held inplace by circumferentially spaced bolts 36, washers 37 being provided onsaid bolts and overlie the edge 25 of the sheath, and nuts 38 serve tosecure the sheath in position.

A threaded post 39 extends outwardly from the face of the sheath S and abafiie plate 40 is mounted on said post in spaced relation with thesheath and is held in position by means of nuts 41 as usual. This baffle40 is positioned vertically as shown, and extends into the air spacebetween the casing and inner shell 12, said batlle being of slightlylarger area than the sheath, and is designed to reflect heat radiatedfrom said sheath and protect the immediate adjacent area in the outercasing from excessive heat radiation. It is therefore important that thebaffle be formed of heat and corrosion resistant metal having properheat resisting characteristics.

A downwardly depending leg 42 is welded or otherwise secured to thelower edge of the baffle plate 40 and extends between the freeprojecting ends of the resistance element to retain them in spacedrelation and prevent short circuits etc., the free end of said leg beingturned as at 43 to eliminate interference with the shaker rod 16.

An opening 44 is provided in the front wall 6 of the casing H to provideeasy access to the heating unit, and a plate 45 forms a closure for saidopening and can be held in place by screws 46 as usual.

When the heating unit is mounted in position in the shell 12, the innerface thereof will be substantially flush with the inner face of saidshell and will be positioned to dehydrate and then ignite any refuseplaced in the combustion chamber, and when the unit is energized, itwill dry and ignite the refuse and will also pre-heat the air flowingupwardly in the casing between the inner and outer shells and into thecombustion chamber, thus assisting in the dehydrating of the refuse andthe incineration thereof.

The heating element must transfer sufficient heat to the sheath to bringit to a temperature where it will ignite the material in the chargingmember. Since the surface area of the sheath is so much greater thanthat of the heating element, it takes some time to bring the sheath tothis temperature, and during this period the refuse in the chamber isthoroughly dried, both by direct radiation from the sheath and itstemperature increases, and by the pro-heating of the air circulatingthrough the chamber.

It will thus be seen that I have perfected a very efficient heating unitfor incinerators which effectively dehydrates and ignites the refuse aswell as preheating the incoming air and with a minimum of currentconsumption.

It is to be understood that the form of the invention shown anddisclosed is to be taken as a preferred embodiment of the invention andthat various changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subioined claims.

What I claim is:

1. The combination with a downdraft incinerator having inner and outerspaced apart shells, the inner shell having an opening therein, of aheating unit which includes a relatively flat sheath releasably mountedin the opening in the inner shell, with its inner face substantiallyflush with the inner shell said sheath having inwardly pressed areascovering the greater portion of the faces of the sheath disposed infacial contact, the space between the edges of said sheath and saidinwardly pressed areas forming a peripheral passage, a heating elementmounted in said passage with its free ends projecting outwardly fromsaid sheath for connection to a source of electrical energy, and abaffle plate supported on said sheath and in the space between the innerand outer shell forming a radiating surface for preheating incoming airand protecting the outer shell from excessive heat.

2. The combination with a garbage incinerator having inner and outerspaced apart shells, a heating unit which includes a relatively flatsheath mounted in the inner shell with its inner face substantiallyflush with the inner face of the inner shell, centrally disposedinwardly pressed sections in said sheath covering substantially thefaces thereof and circumferentially spaced louvers provided in saidsections, a substantially circular heating unit mounted in said sheatharound the inwardly pressed sections with its free ends projecting fromthe lower end of its sheath and connected to a source of electricalenergy, a baffle plate mounted on said sheath and positioned in thespace between the inner and outer shell, and a depending leg on saidbafile extending between the projecting free ends of the heating elementfor maintaining them in spaced relation.

3. A heating unit for refuse incinerators comprising a relatively flatsheath adapted to be releasably mounted in the front wall of theincinerator combustion chamber with its face substantially flush withthe inner face of the chamber wall, said sheath comprising a pair ofoppositely disposed dished plates with the extreme edges thereof weldedtogether, inwardly pressed, centrally disposed areas covering thegreater portion of the faces of the sheath formed in each plate anddisposed in facial contact when the plates are assembled, the spacebetween the edge sections and the inwardly pressed areas forming aperipheral passage, said sheath having an opening therein communicatingwith said peripheral passage, a split annular heating element in saidperipheral passage extending but once around said sheath with its freeend sections proectmg through the opening in the sheath for connectionto a source of electrical energy, and circumferentially spaced ventsthrough said inwardly pressed areas for dissipating heat generatedtherein.

4. The combination defined in claim 1 in which a split annular heatingelement is provided in said peripheral passage extending but once aroundsaid sheath with the free tends thereof projecting from said sheath atcontiguous porn s. 5. The combination with a downdraft incineratorhaving inner and outer substantially vertically disposed spaced apartshells forming a passage therebetween for air to flow upwardlytherethrough, of a sheath mounted in the inner shell, a heating elementmounted in said sheath, a laterally extending support on said sheath,and a substantially vertically disposed plate on said support in saidpassage forming a radiating surface for preheating incoming air andprotecting the outer shell.

6. A heating unit for refuse incinerators comprising a relatively flatsheath adapted to be releasably mounted in the front wall of theincinerator combustion chamber with its face substantially flush withthe inner face of the chamber wall, said sheath comprising a pair ofoppositely disposed dished plates with the extreme edges thereof weldedtogether, inwardly pressed, centrally disposed areas covering thegreater portion of the faces of the sheath formed in each plate anddisposed in facial contact when the plates are assembled, the spacebetween the edge sections and the inwardly pressed areas forming aperipheral passage, a heating element in said peripheral passage withits free end sections projecting from the sheath for connection to asource of electrical energy, circumferentially spaced vents in saidinwardly pressed areas for dissipating heat generated therein, alaterally projecting threaded post extending from the one face of thesheath, and a battle plate adjustably mounted on said post in spacedrelation with the adjacent face of said sheath.

7. A heating unit for refuse incinerators comprising a relatively flatsheath adapted to be releasably mounted in the front wall of theincinerator combustion chamber with its face substantially flush withthe inner face of the chamber wall, said sheath comprising a pair ofoppositely disposed dished plates with the extreme edges thereof weldedtogether, inwardly pressed, centrally disposed areas covering thegreater portion of the faces of the sheath formed in each plate anddisposed in facial contact when the plates are assembled, the spacebetween the edge sect1ons and the inwardly pressed areas forming aperipheral passage, a heating element in said peripheral passage withits free end sections projecting from the sheath for con nectton to asource of electrical energy, circumferentially spaced vents in saidinwardly pressed areas for dissipating heat generated therein, a portionof said sheath being cut away and the free ends of the heating elementextending laterally from said sheath in parallel, spaced relation, abaffle plate mounted on said sheath and spaced from the ad acent facethereof, and means on said baffle for holding the ends of the heatingelement in spaced relation.

References Cited in the file of this patent UNITED STATES PATENTS1,129,381 Carlson Feb. 23, 1915 2,109,163 Carlson Feb. 22, 1938 2.438405Hebert Nov. 15, 1949 2,525,850 Andersen Oct. 17, 1950 2,547,402 Lucas etal Apr. 3, 1951 FOREIGN PATENTS 329,478 Great Britain May 22, 1930

